Living biomembrane bitemplate route for simultaneous synthesis of different morphologies of CdSe and ZnSe nanomaterials

2006 ◽  
Vol 84 (5) ◽  
pp. 782-787 ◽  
Author(s):  
Li Li ◽  
Qing-Sheng Wu ◽  
Ya-Ping Ding
Keyword(s):  
Formation Mechanism ◽  
Room Temperature ◽  
Hexagonal Structure ◽  
Lattice Constants ◽  
Biomineralization Process ◽  
Cubic Structure ◽  
Simultaneous Synthesis ◽  
Xrd Patterns

In this paper, CdSe (nanotubes, nanorods) and ZnSe (nanorods, nanoslats) were simultaneously synthesized through a biomineralization process through biomembrane bitemplates of mungbean sprouts at room temperature. The XRD patterns indicated that these nanocrystals were crystallized in the hexagonal structure and cubic structure with lattice constants a = 0.423 and c = 0.701 nm (CdSe) and a = 0.567 nm (ZnSe), respectively. The possible formation mechanism was investigated in the paper.Key words: CdSe, ZnSe, nanotubes, nanorods, nanoslats, living biomembrane, bitemplates.

Mechanosynthesis, Radiation-Thermal Modification and Characterization of Nanostructured Scandia Stabilized Zirconia Ceramics

2008 ◽  
Vol 1122 ◽  
Author(s):  
Vladimir V. Zyryanov ◽  
Nikolay F. Uvarov ◽  
Artem S. Ulihin ◽  
Vladislav A. Sadykov
Keyword(s):  
Solid Electrolytes ◽  
Room Temperature ◽  
Complex Impedance ◽  
Impedance Method ◽  
Sintering Aids ◽  
Zirconia Ceramics ◽  
Operation Temperature ◽  
Cubic Structure ◽  
Xrd Patterns

AbstractSSZ-based ceramics were obtained by sintering of nanopowders derived at room temperature by mechanochemical synthesis from refined technical grade ZrO2 nano-precursors. RT-treatment by 2.5 MeV electrons up to 1563 K was used for the modification of ceramics. Powders and ceramics were characterized by XRD, Raman, SEM and EDS, TEM, SIMS techniques. The phase composition of Zr0.89Sc0.1Ce0.01O1.95 ceramics was very close to cubic structure but better fitting of XRD patterns was obtained for rhombohedral lattice. Conductivity of solid electrolytes for IT SOFC was studied by complex impedance method. To stabilize cubic structure and increase conductivity at operation temperature of To ∼ 1000 K, the composition of SSZ solid electrolyte was optimized by addition of yttria and sintering aids. The interaction of admixtures with minor dopants leading to intergrain phase was revealed. During fast sintering, ceramics keep a memory about inhomogeneous disordered solid solutions in a form of nanostructuring. Conductivity data indicate nanostructuring of ceramics too: activation energies of bulk and grain boundary conductivities are close (Eb ∼ 0.9 eV, Egb ∼ 1.05 eV). Annealing of ceramics at high temperatures increases conductivity at To and promotes grain growth.

Systematics of Silicide Formation by High Dose Miplantation of Transition Metals into Si

1986 ◽  
Vol 74 ◽  
Author(s):  
F. Namavar ◽  
F. H. Sanchez ◽  
J. I. Budnick ◽  
A. H. Fasihuddin ◽  
H. C. Hayden
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
High Dose ◽  
List Type ◽  
Type Number ◽  
Silicide Formation ◽  
Metal Thin Films ◽  
X Ray ◽  
Cubic Structure ◽  
Fe Implantation

AbstractWe have systematically studied the formation of transition-metal thin films by high dose (up to 1018 ions/cm2) implantation of Ti, V, Cr, Mn, Fe, Co, Ni and Nb at room temperature and 350°C into Si <100>.For implantation at 350°C, our results, as obtained by Rutherford backscattering, X-ray diffractometry and Read Camera measurements, indicate that one can categorize these metals into two groups: 1.a chromium group which includes V, Cr, Nb, Ti and Mn. Metals V, Cr and Nb form compounds (VSi2, CrSi2. NbSi2) with a hexagonal structure of the CrSi2 type whereas Ti and Mn both form compounds (Ti5Si3, Mn5Si3) with a hexagonal structure of the Mn5Si2 type.2.an iron group which includes Fe, Co and Ni. These metals form compounds (FeSi, CoSi, NiSi) with a cubic structure of the FeSi type.In this paper the experimental results for Cr and Fe implantation at room temperature and 350°C will be discussed.

Structural and Magnetic Hysteresis Properties of Co-Zr Substituted Hexagonal Barium Ferrites

2015 ◽  
Vol 7 (1) ◽  
pp. 1346-1351
Author(s):  
Ch.Gopal Reddy ◽  
Ch. Venkateshwarlu ◽  
P. Vijaya Bhasker Reddy
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Grain Morphology ◽  
Hexagonal Structure ◽  
Ion Composition ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
Barium Ferrites ◽  
Xrd Patterns

Co-Zr substituted M-type hexagonal barium ferrites, with chemical formula BaCoxZrxFe12-2xO19 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), have been synthesized by double sintering ceramic method. The crystallographic properties, grain morphology and magnetic properties of these ferrites have been investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirm the single phase with hexagonal structure of prepared ferrites. The magnetic properties have been investigated as a function of Co and Zr ion composition at an applied field in the range of 20 KOe. These studies indicate that the saturation magnetization (Ms) in the samples increases initially up to the Co-Zr composition of x=0.6 and decreases thereafter. On the other hand, the coercivity (Hc) and Remanent magnetization (Mr) are found to decrease continuously with increasing Co-Zr content. This property is most useful in permanent magnetic recording. The observed results are explained on the basis of site occupation of Co and Zr ions in the samples.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

Formation Mechanism and Chirality Evolution of Chiral Carbon Dots Prepared via Radical Assisted Synthesis at Room Temperature

Nanoscale ◽  
2021 ◽  
Author(s):  
Lorenzo Branzi ◽  
Giacomo Lucchini ◽  
Elti Cattaruzza ◽  
Nicola Pinna ◽  
Alvise Benedetti ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Formation Mechanism ◽  
Carbon Dots ◽  
Room Temperature ◽  
Chiral Carbon

We report on a Cu(II) catalyzed process for the production of cysteine based chiral carbon dots, the process does not require any thermal treatment and the carbon dots formation is...

Topological crystallography of gas hydrates

2015 ◽  
Vol 71 (4) ◽  
pp. 444-450 ◽  
Author(s):  
Sergey V. Gudkovskikh ◽  
Mikhail V. Kirov
Keyword(s):  
Hydrogen Bonding ◽  
Gas Hydrates ◽  
Periodic Boundary ◽  
Periodic Boundary Conditions ◽  
Hexagonal Structure ◽  
New Approach ◽  
Quotient Graphs ◽  
Disordered Structure ◽  
Unit Cells ◽  
Cubic Structure

A new approach to the investigation of the proton-disordered structure of clathrate hydrates is presented. This approach is based on topological crystallography. The quotient graphs were built for the unit cells of the cubic structure I and the hexagonal structure H. This is a very convenient way to represent the topology of a hydrogen-bonding network under periodic boundary conditions. The exact proton configuration statistics for the unit cells of structure I and structure H were obtained using the quotient graphs. In addition, the statistical analysis of the proton transfer along hydrogen-bonded chains was carried out.

Room temperature Mg reduction of TiO2: formation mechanism and application in photocatalysis

2019 ◽  
Vol 55 (53) ◽  
pp. 7675-7678 ◽  
Author(s):  
Di Zu ◽  
Zhongfei Xu ◽  
Ao Zhang ◽  
Haiyang Wang ◽  
Hehe Wei ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Formation Mechanism ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Oxide Structure

A Mg/HCl infiltrated metal oxide structure was designed as a facile approach for implanting oxygen vacancies and H atoms into metal oxides.

STRUCTURE AND MAGNETIC PROPERTIES OF MECHANICAL ALLOYED Mn-15at.%Al

2013 ◽  
Vol 12 (01) ◽  
pp. 1350006
Author(s):  
AHMED E. HANNORA ◽  
FARIED F. HANNA ◽  
LOTFY K. MAREI
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Average Crystallite Size ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Milled Sample ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Method Analysis

Mechanical alloying (MA) method has been used to produce nanocrystallite Mn -15at.% Al alloy. X-ray diffraction (XRD) patterns for the as-milled elemental α- Mn and aluminum powder samples show a mixture of α + β- MnAl phases after 20 h of milling and changes to a dominant β- MnAl phase structure after 50 h. An average crystallite size of 40 nm was determined from Hall–Williamson method analysis after 5 h of milling. Moreover, the thermal analysis results using differential thermal analysis (DTA), suggested a possible phase transformation after 20 h of milling. Isothermal treatments are carried in the temperature range of 450°C to 1000°C. Room-temperature vibrating sample magnetometer (VSM) measurements of the hysteretic response revealed that the saturation magnetization Bs and coercivity Hc for 10 h ball milled sample are ~ 2.1 emu/g and ~ 92 Oe, respectively.

scholarly journals Structural and Optical Properties of Cobalt-Doped Zinc Oxide Thin Films Prepared By Spray Pyrolysis Technique

2010 ◽  
Vol 7 (1) ◽  
pp. 69-75
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Optical Properties ◽  
Spray Pyrolysis ◽  
Spray Pyrolysis Technique ◽  
Texture Coefficient ◽  
Hexagonal Structure ◽  
Structural And Optical Properties ◽  
Lattice Constants ◽  
Glass Substrates

Undoped and Co-doped zinc oxide (CZO) thin films have been prepared by spray pyrolysis technique using solution of zinc acetate and cobalt chloride. The effect of Co dopants on structural and optical properties has been investigated. The films were found to exhibit maximum transmittance (~90%) and low absorbance. The structural properties of the deposited films were examined by x-ray diffraction (XRD). These films, deposited on glass substrates at (400? C), have a polycrystalline texture with a wurtzite hexagonal structure, and the grain size was decreased with increasing Co concentration, and no change was observed in lattice constants while the optical band gap decreased from (3.18-3.02) eV for direct allowed transition. Other parameters such as Texture Coefficient (Tc), dislocation density (?) and number of crystals (M) were also calculated .

Structural, Optical and Magnetic Properties of Co and Fe Doped ZnO Thin Films Grown by Radio Frequency Magnetron Sputtering

2006 ◽  
Vol 957 ◽  
Author(s):  
Luis Manuel Angelats ◽  
Maharaj S Tomar ◽  
Rahul Singhal ◽  
Oscar P Perez ◽  
Hector J Jimenez ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Rf Magnetron Sputtering ◽  
Visible Range ◽  
Radio Frequency Magnetron Sputtering ◽  
Optical And Magnetic Properties ◽  
Doped Zno ◽  
Xrd Patterns ◽  
Antiferromagnetic Behavior

ABSTRACTZn0.90Co0.10O and Zn0.85[Co0.50Fe0.50]0.15O targets were used to grow thin films by rf magnetron sputtering. XRD patterns of the films showed a strong preferred orientation along c-axis. Zn0.90Co0.10O film showed a transmittance above 75% in the visible range, while the transmittance of the Zn0.85[Co0.50Fe0.50]0.15O film was about 45%; with three absorption peaks attributed to d-d transitions of tetrahedrally coordinated Co2+. The band gap values for Zn0.90Co0.10O and Zn0.85[Co0.50Fe0.50]0.15O films were 2.95 and 2.70 eV respectively, which are slightly less than ZnO bulk. The Zn0.90Co0.10O film showed a relatively large positive magnetoresistance (MR) at the high magnetic field in the temperature range from 7 to 50 K, which reached 11.9% a 7K for the magnetoresistance. The lowest MR was found at 100 K. From M-H curve measured at room temperature shown a probable antiferromagnetic behavior, although was possible to observe little coercive field of 30 Oe and 40 Oe for Zn0.90Co0.10O and Zn0.85[Co0.50Fe0.50]0.15O films, respectively.

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